Shell Programming and Scripting

col1 col2 col3
11 ssa 13.60
12 ssb 11.00
13 ssc 754.00

col1 col2 col3
11 sa 12.75
12 sb 11.00
13 sc 763.00

awk 'BEGIN {print "In file_2 value is:"} FNR==NR {a[$1]=$3;next} $1 in a {if ($3==a[$1]) t="equal"; else if ($3<a[$1]) t="less"; else {t="greater"};print $1,t}' file_1 file_2
In file_2 value is:
11 less
12 equal
13 greater

awk '
	BEGIN {print "In file 2 value is:"}
	FNR==NR {
		a[$1]=$3;next} 
	$1 in a {
		if ($3==a[$1]) t="equal"
			else if ($3<a[$1]) t="less"
			else {t="greater"
			}
	print $1,t}
	' 1 2

col1 col2 col3
11 ssa 13.60
12 ssb 11.00
13 ssc 754.00

col1 col2 col3
11 sa 12.75
12 sb 11.00
13 sc 763.00

$ awk 'FNR==NR {a[$1]=$3;next} $1 in a {if ($3==a[$1]) t=0; else {t=$3-a[$1]};print $0,t}' 1.txt 2.txt 
11 sa 12.75 -0.85
12 sb 11.00 0
13 sc 763.00 9

11 sa 12.75
 -0.85 12 sb 11.00 
  0 13 sc 763.00 
  9

$ awk 'FNR==NR {a[$1]=$3;next} {OFS=" "} $1 in a {if ($3==a[$1]) t=0; else {t=$3-a[$1]};print $0,t}' 1.txt 2.txt